Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
3. Functions
Function Composition
Problem 31d
Textbook Question
Determine whether each function graphed or defined is one-to-one. y = 5|x+2|
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1
Understand the definition of a one-to-one function: A function is one-to-one if each output value is paired with exactly one input value, meaning it passes the horizontal line test.
Consider the given function: \( y = 5|x+2| \). This is an absolute value function, which typically has a 'V' shape when graphed.
Graph the function \( y = 5|x+2| \). The vertex of the graph is at \( x = -2 \), and the graph opens upwards with a slope of 5 on either side of the vertex.
Apply the horizontal line test: Draw horizontal lines across the graph. If any horizontal line intersects the graph at more than one point, the function is not one-to-one.
Observe that for \( y = 5|x+2| \), horizontal lines will intersect the graph at two points for any \( y > 0 \), indicating that the function is not one-to-one.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
One-to-One Function
A one-to-one function is a type of function where each output value is associated with exactly one input value. This means that no two different inputs produce the same output. To determine if a function is one-to-one, one can use the horizontal line test: if any horizontal line intersects the graph of the function more than once, the function is not one-to-one.
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Absolute Value Function
An absolute value function is defined as f(x) = |x|, which outputs the non-negative value of x. The graph of an absolute value function is V-shaped, with a vertex at the origin. In the case of the function y = 5|x + 2|, the graph is vertically stretched by a factor of 5 and shifted left by 2 units, affecting its symmetry and one-to-one nature.
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Graphical Analysis
Graphical analysis involves examining the visual representation of a function to understand its properties, such as continuity, intercepts, and whether it is one-to-one. By analyzing the shape and behavior of the graph, one can apply tests like the horizontal line test to determine if the function meets specific criteria, such as being one-to-one.
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